The goal of this project is analyze the behavior of three quantum key distribution protocols (QKD): BB84, B92 and EPR, with the intention of comparing each of them for different scenarios. First of all, the elementary concepts of quantum computing are defined: superposition, qubit, state collapse and entanglement. Next, a brief introduction of the basics of quantum cryptography is made. After introducing the theoretical frame, the development through MATLAB of the script that will simulate the QKD session for each protocol is presented. For the set of scenarios studied, the simulations obtained are analyzed in order to compare the operation of each protocol. In this way, we can analyze the robustness of the protocols according to the different factors that can act during a QKD session such as the error introduced by the channel, the measurement error in the reception and, from a security point of view, the one we are most interested in detecting is the measurement made by an intruder. Finally, a real scenario is analyzed and losses for the following quantum channels are estimated: optical fiber and free space.